Heating arrangements for humidification systems

ABSTRACT

An electrically conductive plastic (ECP) material can be used to heat water in a reservoir of a respiratory humidifier to encourage heating and/or humidification of gases passing through the respiratory humidifier. The electrically conductive plastic material can at least in part overmould the base and/or walls of the chamber and/or the reservoir of the respiratory humidifier. The reservoir can also partially or fully be formed from the electrically conductive plastic material. Furthermore, the humidification system can be configured to create substantially equal or differential heating of water in the reservoir.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention generally relates to humidification devices. Moreparticularly, the present invention relates to heating arrangements foruse with respiratory devices.

Description of the Related Art

Respiratory disorders deal with the inability of a sufferer to effect asufficient exchange of gases with the environment, leading to animbalance of gases in the sufferer. These disorders can arise as apathological consequence of an obstruction of the airway, insufficiencyof the lungs in generating negative pressure, an irregularity in thenervous function of the brain stem, or some other physiologicalcomplication. Treatment of such disorders is diverse and depends on theparticular respiratory disorder being targeted. In the first instance, aconstriction of the airway, otherwise known as an obstructive apnea or ahypopnea (collectively referred to as obstructive sleep apnea or OSA),can occur when the muscles that normally keep the airway open in apatient relax during slumber to the extent that the airway isconstrained or completely closed off, a phenomenon often manifestingitself in the form of snoring. When this occurs for a significant periodof time, the patient's brain typically recognizes the threat of hypoxiaand partially wakes the patient in order to open the airway so thatnormal breathing may resume. The patient may be unaware of theseoccurrences, which may occur as many as several hundred times persession of sleep. This partial awakening may significantly reduce thequality of the patient's sleep, over time potentially leading to avariety of symptoms, including chronic fatigue, elevated heart rate,elevated blood pressure, weight gain, headaches, irritability,depression and anxiety.

Obstructive sleep apnea is commonly treated with the application ofpositive airway pressure (PAP) therapy, PAP therapy involves deliveringa flow of gas to a patient at a therapeutic pressure above atmosphericpressure that will reduce the frequency and/or duration of apneas,hypopneas, and/or flow limitations. This therapy is often delivered byusing a positive airway pressure device (PAP device) to propel apressurized stream of air through a conduit to a patient through aninterface or mask located on the face of the patient. The stream of airmay be heated to near body temperature. The stream of air may behumidified. The humidification may be performed by forcing the stream ofair to travel through a respiratory humidifier containing water and aheater for heating the water. In such a system, the heater encouragesthe evaporation of the water, which in turn imbues the stream of airwith moisture and/or heat. This moisture and/or heat may help toameliorate discomfort that may arise from the use of unhumidified PAPtherapy. Respiratory humidifiers may also be used with other gas-basedtherapies, such as high flow therapy, and may have similar therapeuticbenefits when used with other gas-based therapies.

SUMMARY OF THE INVENTION

In some cases, when utilizing a respiratory therapy system involving theadministration of gases, it is desired to use a respiratory humidifierto heat and/or humidify the gases being delivered to a patient. Therespiratory humidifier may comprise a humidification chamber comprisinga resistive metallic heating plate and a reservoir that may interfacewith the resistive metallic heating plate. The gas may pass through thereservoir and/or humidification chamber. The resistive metallic heatingplate may be used to heat liquid contained in the reservoir to encourageliquid entrainment in the gas flow. However, there may be difficulty inthe industrial use of some such resistive metallic heating plates. Manymetals may be difficult and/or expensive to mold into desired shapes.The price of the raw material used to craft a resistive metallic heatingplate may be high. The electrical and/or thermal conductivity of theresistive metallic heating plate may not be ideal. A resistive metallicheating plate, if used in a humidification chamber, may not blendseamlessly with the rest of the humidification chamber, and may not beaesthetically pleasing to a consumer. Accordingly, it is an object ofthe disclosure to provide an improved heating system that might solveone or more of the above problems, or at least provide the public with auseful choice.

Thus, in accordance with at least one of the embodiments disclosedherein, a humidifier is disclosed. The humidifier may be a respiratoryhumidifier. The humidifier may comprise a reservoir. The humidifier maycomprise a base. The base may define a region configured to accommodatethe reservoir. The humidifier may comprise a chamber for receiving thereservoir. The heater may be located in or may form part of the baseand/or reservoir and/or chamber. The heater may at least in part beconstructed from an electrically conductive plastic material. The basemay be part of a chamber. The heater may be configured to promotedifferential heating of liquid in the reservoir. The heater may have avariable thickness along its length and/or width.

In some configurations, the heater may be directly or indirectlyconnected to a source of power. In some configurations, the heater maybe connected to the source of power by an electrical conductor. In someconfigurations, the heater may be wirelessly connected to the source ofpower.

In some configurations, the base may be at least partially overmouldedwith the heater. In some configurations, the base is at least in partdiscontinuously overmoulded with the heater. In some configurations, thebase is fully or completely overmoulded with the heater.

In some configurations, the reservoir has at least partially been formedfrom the heater. In some configurations, the reservoir has discontinuousportions at least partially formed from the heater. In someconfigurations, the reservoir has been wholly formed from the heater.

In some configurations, the reservoir comprises a bottom section. Theheater may at least partially overmould the bottom section. In someconfigurations, the heater may fully overmould the bottom section. Insome configurations, the reservoir comprises a side wall. The heater mayat least partially overmould the side wall. In some configurations, theheater may fully overmould the side wall. In some configurations, theheater may have an irregular thickness. The irregular thickness may bealong the width and/or length of the heater. In some configurations, theelectrically conductive plastic material comprises polyphenylenesulfide.

In accordance with another embodiment disclosed herein, a humidifier isdisclosed. The humidifier may comprise a chamber for receiving areservoir. The humidifier may comprise a heater for heating liquid inthe reservoir. The heater may be located in or form part of the chamber.The humidifier may comprise a reservoir and the heater may be located inor form part of the reservoir. The heater may be configured to promotedifferential heating of liquid in the reservoir. The heater may comprisea variable thickness along its length and/or width.

In accordance with another embodiment disclosed herein, a humidificationsystem is disclosed. The humidification system may comprise a heaterhaving a variable thickness along its length and/or width. The heatermay comprise a contoured first surface that comprises two crestsseparated by a trough. The trough may be positioned along the heater atan off centre location. The humidification system may compriseelectrical connectors at opposing ends of the trough. The humidificationsystem may comprise a reservoir. The heater may be present in thereservoir. The humidification system may comprise a chamber. The heatermay be present in the chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain features, aspects and advantages of specific embodiments andmodifications of the present invention will become apparent to thoseskilled in the art from the detailed description herein having referenceto the figures that follow, of which:

FIG. 1 shows a schematic diagram of a respiratory therapy system.

FIG. 2 illustrates a humidifier configuration in which a base of achamber of the humidifier has been overmoulded with an electricallyconductive plastic material.

FIG. 3 illustrates a humidifier configuration in which a base of achamber of the humidifier has overmoulded an electrically conductiveplastic material.

FIG. 4A illustrates a configuration for an electrically conductiveplastic material.

FIG. 4B illustrates a configuration for an electrically conductiveplastic material.

FIG. 4C illustrates a configuration for an electrically conductiveplastic material.

FIG. 4D illustrates a configuration for an electrically conductiveplastic material.

FIG. 4E illustrates a configuration for an electrically conductiveplastic material.

FIG. 4F illustrates a configuration for an electrically conductiveplastic material.

FIG. 5A illustrates a humidifier configuration wherein the entirereservoir has been constructed from an electrically conductive plasticmaterial.

FIG. 5B illustrates a humidifier configuration wherein a part of thereservoir has been constructed from an electrically conductive plasticmaterial.

FIG. 5C illustrates a humidifier configuration wherein a part of thereservoir has been constructed from an electrically conductive plasticmaterial.

FIG. 5D illustrates a humidifier configuration wherein a part of thereservoir has been constructed from an electrically conductive plasticmaterial.

FIG. 5E illustrates a humidifier configuration wherein a part of thereservoir has been constructed from an electrically conductive plasticmaterial.

FIG. 5F illustrates a humidifier configuration wherein a part of thereservoir has been constructed from an electrically conductive plasticmaterial.

FIG. 5G illustrates a humidifier configuration wherein a part of thereservoir has been constructed from an electrically conductive plasticmaterial.

FIG. 6 shows a schematic diagram of current pathways across aconfiguration for a humidifier heater.

FIG. 7 shows another schematic diagram of current pathways across aconfiguration for a humidifier heater.

FIG. 8A illustrates a side view of a configuration for a humidifierheater.

FIG. 8B illustrates a perspective view of the humidifier heater of FIG.8A.

FIG. 9A illustrates a side view of a configuration for a humidifierheater.

FIG. 9B illustrates a perspective view of the heater of FIG. 9A.

FIG. 9C illustrates another perspective view of the heater of FIG. 9A.

FIG. 9D illustrates yet another perspective view of the heater of FIG.9A.

FIG. 10 illustrates a configuration for a humidifier chamber.

FIG. 11 illustrates an exploded view of a configuration for ahumidifier.

FIG. 12 illustrates a partially exploded view of the configuration ofFIG. 11.

FIG. 13 illustrates a perspective view of a configuration for ahumidifier.

FIG. 14 shows a schematic diagram of current pathways across aconfiguration for a humidifier heater.

FIG. 15A shows a top view of a reservoir comprising internal vanes.

FIG. 15B shows a top view of a reservoir and an insert adapted to beused with the reservoir.

FIG. 15C shows a perspective view of an insert adapted to be used with areservoir.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Certain features, aspects and advantages of at least one of theconfigurations disclosed herein include the realization that anelectrically conductive plastic (ECP) material may be used as a heaterfor assisting in the heating and/or humidification of gases delivered bya respiratory therapy system. The ECP material may, for example, be usedin a respiratory humidifier to heat water contained in a reservoir suchthat water vapour may be generated. The water vapour may join gasespassing through the respiratory humidifier and/or reservoir to providehumidified gases to a patient.

With reference to FIG. 1, a configuration for a respiratory therapysystem 100 is shown. In the illustrated configuration, the respiratorytherapy system 100 may comprise a flow generator 101. The flow generator101 may comprise a gas inlet 102 and a gas outlet 104. The flowgenerator may comprise a blower 106. The blower 106 may comprise amotor. The motor may comprise a stator and a rotor. The rotor maycomprise a shaft. An impeller may be linked to the shaft. In use, theimpeller may rotate concurrently with the shaft to draw in gas from thegas inlet 102. The flow generator 101 may comprise a user interface 108which may comprise one or more buttons, knobs, dials, switches, levers,touch screens, and/or displays so that a user might view data related tothe operation of the flow generator 101 or to other components of therespiratory therapy system 100 or input operation parameters into theflow generator 101 to control its operation or the operation of othercomponents of the respiratory therapy system 100. The flow generator 101may pass gas through the gas outlet 104 to a first conduit 110. Thefirst conduit 110 may pass the gas to a humidifier 112 that may entrainmoisture in the gas to provide a humidified gas stream. The humidifier112 may comprise a humidifier inlet 116 and a humidifier outlet 118. Thehumidifier 112 may comprise a reservoir 114 that may be filled withwater or some other humidifying agent (hereinafter referred to aswater). The humidifier 112 may comprise a chamber (not shown). Thechamber may serve as a housing or support for the reservoir 114. Thehumidifier 112 may comprise a heater 113 that may be used to heat thewater in the reservoir 114 to encourage water vaporization and/orentrainment in the gas flow and/or increase the temperature of gasespassing through the humidifier 112. The humidifier 112 may have a userinterface 120 which may comprise one or more buttons, knobs, dials,switches, levers, touch screens, and/or displays so that a user mightinput operation parameters into the humidifier 112 to view data relatedto the operation of the humidifier 112 or to other components of therespiratory therapy system 100 or control the operation of the heater113 and/or operation of other aspects of the humidifier 112 orrespiratory therapy system 100. Gas may then pass from the humidifieroutlet 118 to a second conduit 122. The second conduit 122 may comprisea conduit heater (not shown) that may be used to add heat to gasespassing through the second conduit 122. The heat may help to prevent thecondensation of moisture entrained in the gas stream along the walls ofthe second conduit 122. The conduit heater may comprise one or moreresistive wires located in, on, or around a wall of the second conduit122. Gas passing through the second conduit 122 may then enter a patientinterface 124 that may pneumatically link the respiratory therapy system100 to the patient's airway. The patient interface 124 may comprise anasal mask, an oral mask, an oro-nasal mask, a full face mask, a nasalpillows mask, a nasal cannula, an endrotracheal tube, a combination ofthe above or some other gas conveying system.

In the illustrated configuration, and as implied above, the respiratorytherapy system 100 may operate as follows. Gas may be drawn into theflow generator 101 through the gas inlet 102 due to the rotation of animpeller of the motor of the blower 106. Gas may then be propelled outof the gas outlet 104 and along the first conduit 110. The gas flow mayenter the humidifier 112 through the humidifier inlet 116. Once in thehumidifier 112, the gas may pick up moisture while passing over thewater in the reservoir 114. The reservoir 114 may be heated by theheater 113, which may aid in the humidification and/or heating of thegas passing through the respiratory humidifier 112. The gas may leavethe humidifier 112 through a humidifier outlet 118 and enter a secondconduit 122. Gas may be passed from the second conduit 122 to thepatient interface 124, where the gas may be taken into the patient'sairways to aid in the treatment of respiratory disorders.

The illustrated configuration should not be taken to be limiting; manyother configurations for the respiratory therapy system 100 arepossible. In some configurations, the flow generator 101 may, forexample, comprise a source or container of compressed gas (e.g. air).The container may comprise a valve that may be adjusted to control theflow of gas leaving the container. In some configurations, the flowgenerator 101 may use such a source of compressed gas and/or another gassource in lieu of a blower 106. In some configurations, the blower 106may be used in conjunction with another gas source. In someconfigurations, the flow generator 101 may draw in atmospheric gasesthrough the gas inlet 102. In some configurations, the flow generator101 may be adapted to both draw in atmospheric gases through the gasinlet 102 and accept other gases (e.g. oxygen, nitric oxide, carbondioxide, etc) through the same gas inlet 102 or a different inlet. Insome configurations, the humidifier 112 can be integrated with the flowgenerator 101. In some configurations, the humidifier 112 and the flowgenerator 101 may share a housing 125. In some such configurations, onlya single conduit extending between the flow generator 101 and thepatient interface 124 need be used to convey gases to a patient. In someconfigurations, the flow generator 101 and the humidifier 112 may have asingle user interface located on either the flow generator 101 or thehumidifier 112. In some configurations, the operation of the flowgenerator 101, of the humidifier 112, or of other aspects of therespiratory therapy system 100 may be controlled by a controller. Thecontroller may comprise a microprocessor. The controller may be locatedin or on the flow generator 101, the humidifier 112, or other parts ofthe respiratory therapy system 100. In some configurations, multiplecontrollers may be used. In some configurations, the operation of theflow generator 101, of the humidifier 112, or of other aspects of therespiratory therapy system 100 may be controlled wirelessly using a userinterface located on a remote computing device. In some configurations,the respiratory therapy system 100 may comprise one or more sensors fordetecting various characteristics of the gas, including pressure, flowrate, temperature, absolute humidity, relative humidity, enthalpy,oxygen concentration, and/or carbon dioxide concentration. Measurementsobtained using the one or more sensors may be utilized by the controllerto facilitate open or closed loop control of one or more components ofthe respiratory therapy system 100, including but not limited to theflow generator 101, the humidifier 112, the heater 113 and/or theconduit heater of the second conduit 122. In some configurations, theremay be no user interface or a minimal user interface for the flowgenerator 101, humidifier 112, or other aspects of the respiratorytherapy system 100. In some such configurations, the respiratory therapysystem 100 may utilize a sensor to determine if the patient isattempting to use the respiratory therapy system 100. In suchconfigurations, the respiratory therapy system may automatically operate(e.g., the flow generator 101 may propel gases, the humidifier 112 mayhumidify gases, etc.) according to one or more predetermined parametersif the sensor indicates that the patient is attempting to use therespiratory therapy system 100.

Attention is now given to the discussion of ECP materials. An ECPmaterial may comprise a synthetic or natural resin, a plastic, apolymer, a composition of a resin, plastic, or polymer, or anothermaterial that is electrically conductive and has plastic qualities orcharacteristics. In some configurations, the ECP material may comprise athermoplastic material, e.g., a material that becomes moldable orpliable if the temperature of the material is raised to a particulartemperature and that returns to a solid, relatively firm state uponcooling. In some configurations, the ECP material may, for example,comprise plastics or polymers that are intrinsically electricallyconductive, such as polyphenylene sulfides, polyacetylenes,polyanilines, polypyrroles, polythiophenes, polyphenylenes,polyphenylene vinylenes (such as poly(p-phenylene vinylene)),polyalkylthiophenes, polypyrenes, polyazulenes, polynaphthalenes,polycarbazoles, polyindoles, polyazepines, polyethylenedioxythiophenes(such as poly(3,4-ethylenedioxythiophene)), polymers comprising metalatoms, and polymer-metal complexes. In some configurations, the ECPmaterial may comprise an electrically conductive additive or dopingagent, such as carbon black, carbon fibers, carbon nanotubes, graphite,graphene, stainless steel fibers, metal flakes or powders (e.g. gold,silver, copper, etc), metal composites, organometallic complexes,phthalocyanine salts, and polycyclic aromatic hydrocarbons. In some suchconfigurations, plastics or polymers that are not intrinsicallyelectrically conductive may be used. Preferably, the ECP material may besuitable for use as a resistive heater.

With reference to FIGS. 4A-4F, an ECP structure 133 is shown. The ECPstructure 133 may comprise an ECP material layer 140. In the illustratedconfiguration, the ECP material layer 140 is the form of a film.However, the ECP material layer 140 may comprise other geometries, suchas strands or blocks. In some configurations, the ECP structure 133 maycomprise a first supporting layer 134 and/or a second supporting layer135. The layer of ECP material 140 may be in physical communication withthe first or second supporting layers 134, 135. Alternatively, the layerof ECP material 140 may be in physical communication with both the firstand second supporting layers 134, 135 so that the ECP layer 140 issubstantially sandwiched between the first and second supporting layers134, 135. The first supporting layer 134 and/or second supporting layer135 may likewise be in the form of films, or the first and/or secondsupporting layers 134, 135 may comprise other geometries. The firstand/or second supporting layers 134, 135 may comprise thermallyconductive and/or electrically insulative materials. The layer of ECPmaterial 140, first supporting layer 134, and/or second supporting layer135 may be bound together. The binding may be realized through the useof a mechanical fastener, an adhesive, lamination, ultrasonic welding,or through the use of some other binding process or device. In someconfigurations, the layer of ECP material 140, the first supportinglayer 134, and/or the second supporting layers 135 may be a part of anapparatus, for example, a wall or base of a humidification chamber, awall or base of a reservoir, of another component of a humidifier, apatient interface (for example, in or on an internal surface of apatient interface, the internal surface being a surface upon whichcondensed water may be deposited in use), a conduit (for example, as aconduit heater) or of some other respiratory apparatus. As demonstratedin FIG. 4A, the ECP material layer 140 may be entirely constructed froman ECP material. However, in some configurations, the ECP material layer140 may at least in part be constructed from another material. As shownin FIG. 4B, the ECP material layer 140 may be constructed from a sectionof an ECP material and a section of another material. As shown in FIG.4C, the ECP material layer 140 may be constructed from a first sectionof ECP material and a second section opposing the first section ofanother material, where the first section of ECP material has anirregular thickness along the width and/or length of the ECP materiallayer 140. As shown in FIG. 4D, the ECP material layer 140 may beconstructed from alternating sections of an ECP material and one or moreother materials. As shown in FIG. 4E, the ECP material layer 140 maycomprise a serpentine track of ECP material in or on another material.Many other configurations may be imagined. The configurations shown inFIGS. 4B-4E may be useful for creating differential heating in a body ofwater heated by the ECP structure 133, which may encourage the formationof convection currents, eddies, and/or other turbulence-inducingphenomena in the body of water such that efficient mixing and/or heatingof the water may be realized. Additionally, in some configurations, andas shown in FIG. 4F, the ECP material layer 140 and/or other parts ofthe ECP structure 133 may interface with an electrical structure 142that may convey electrical and/or thermal energy to the ECP structure133 and/or ECP material layer 140. The electrical structure 142 maycomprise metals (e.g. aluminum bars or other masses) or otherelectrically conductive materials. The electrical structure 142 may inturn receive electrical energy wirelessly or through a wired connectionor electrical lead. The electrical lead may come from a component of arespiratory therapy system, such as, for example, a flow generator or aheated conduit of a respiratory therapy system.

With reference to FIG. 2, a humidifier 112 is shown. The humidifier 112may comprise a reservoir 114 that may in use hold water 130 or anotherhumidification agent (hereinafter referred to as water 130). Thereservoir 114 may comprise a gas inlet 116 and a gas outlet 118. Thehumidifier 112 may comprise a humidification chamber 126 that may in useaccommodate or otherwise define a space for the placement of thereservoir 114. In some configurations, the humidification chamber 126may comprise a gas inlet. The gas inlet of the humidification chamber126 may pneumatically interface with the gas inlet 116 of the reservoir114. In some configurations, the humidification chamber 126 may comprisea gas outlet. The gas outlet of the humidification chamber 126 maypneumatically interface with the gas outlet 118 of the reservoir 114.Many different configurations of inlets and outlets for the humidifier112 may be possible. For example, in some configurations, thehumidification chamber 126 and the reservoir 114 may share a singleconjoined gas inlet that extends from an outer wall of thehumidification chamber 126 to an inner wall of the reservoir 114. Insome configurations, the humidification chamber 126 and the reservoir114 may share a single conjoined gas outlet that extends from an innerwall of the reservoir 114 to an outer wall of the humidification chamber126. In the illustrated configuration of FIG. 2, the humidificationchamber 126 comprises a base 134. The base 134 may be overmoulded withan ECP structure 133. In some configurations, and as demonstrated inFIG. 3, the base may overmould the ECP structure 133. In otherconfigurations, the ECP structure 133 may be secured to the base 134through the use of other methods, including but not limited to welding(for example, ultrasonic or high frequency welding), the use ofadhesives, or the use of mechanical fastening arrangements (for example,hook-and-loop fasteners, screw threading arrangements, bolts, etc). TheECP structure 133 may directly or indirectly interface with anelectrical connection 132. The electrical connection 132 may include,for example, a wire or conductor that may be electrically linked to abattery, a fuel cell, an AC power source or a DC power source. Theelectrical connection 132 may interface with the ECP layer 133 in avariety of ways. In some configurations, the electrical connection 132may include a wire that may protrude through the base 134 of thehumidification chamber 126 or some other wall of the humidificationchamber 126 or opening in the humidification chamber 126 (for example, agas inlet or gas outlet of the humidification chamber 126) to interfacewith the ECP structure 133. In some configurations, no direct electricalconnection 132 is necessary to supply the ECP structure 133 withelectrical energy. For example, the ECP structure 133 may receiveelectrical energy wirelessly by inductive charging or resonant inductivecoupling. The ECP structure 133 may be energized using inductiveelectrical power transfer technology. In some configurations, thetechnology may be similar to technologies used for the Qi interfacestandard for charging mobile devices. In use, the ECP structure 133 mayreceive electrical current from the electrical connection 132 or someother source of electricity. The ECP structure 133 converts theelectrical energy into thermal energy. The thermal energy is passed tothe reservoir 114 containing water 130. In some configurations, thethermal energy generated may be passed to the reservoir 114 through athermally conductive element. The thermally conductive element may bepart of a base 128 or wall of the reservoir 114, may be part of thehumidification chamber 126, or may be part of both the reservoir 114 andthe humidification chamber 126. Thermal energy may pass from thereservoir 114 to the water 130 in the reservoir 114 to heat the water.Water vapor may be generated from the water 130 which then may join theflow of gases passing from the gas inlet 116 to the gas outlet 118. Insome configurations, the thermally conductive element may not bepresent. In some configurations, the reservoir 114 may be whollyconstructed from a thermally conductive material. Advantageously, theECP structure 133 may be used to quickly heat the water 130 while beingeasy to form into desired shapes using conventional molding techniques.Additionally, the cost of the raw materials used to form the ECPstructure 133 may be less than the cost for other more conventionalmaterials usable for heating water 130 in respiratory humidificationsystems. The ECP structure 133 and/or other components of the humidifier122 may comprise or interface with one or more thermistors,thermocouples, or other sensors or sensing modules that may be used tohelp control operation of the humidifier 112 or other parts of arespiratory therapy system 100.

In some configurations, and as demonstrated in FIGS. 5A-5G, thereservoir 114 may be constructed at least in part from an ECP structure133. In some such configurations, the humidification chamber 126 neednot comprise a heating material or separate ECP structure along the base134 or walls of the humidification chamber 126. The electricalconnection 132 may interface directly with one or more sections of thereservoir 114. In other configurations, electrical energy may bedelivered to the reservoir 114 wirelessly as similarly describedelsewhere in this disclosure with reference to FIGS. 2 and 3. In someconfigurations, and as illustrated in FIG. 5A, the entire reservoir 114may be constructed from an ECP structure 133. However, in someconfigurations, only a part of the reservoir 114 may be constructed froman ECP structure 133. As shown in FIG. 5B, the reservoir 114 may beconstructed from a section of an ECP structure 133 and a section ofanother material, such as a non-thermally conductive and/ornon-electrically conductive material. The sections may be on oppositesides of the reservoir 114. As shown in FIG. 5C, the reservoir 114 maybe constructed from a first section of an ECP structure 133 and a secondsection opposing the first section of another material, where the firstsection has an irregular thickness along the width and/or length of thefirst section. As shown in FIG. 5D, the reservoir 114 may be constructedfrom alternating sections of an ECP structure 133 and one or more othermaterials. As shown in FIG. 5E, the base 128 of the reservoir 114 may beconstructed from an ECP structure 133. As shown in FIGS. 5F and 5G, thebase 128 of the reservoir 114 constructed from the ECP structure 133 mayhave an irregular thickness along the width and/or length of the base128. In some configurations, and particularly in the configurationsillustrated in FIGS. 5B, 5C, 5D, 5F, and 5G, differential heating of thewater 130 in the reservoir 114 may occur. The differential heating mayencourage the formation of convection currents, eddies, and/or otherturbulence-inducing phenomena in the body of water such that efficientmixing and/or heating of the water 130 may be realized. The differentialheating effect may be improved as the contact area of the ECP structure133 with the water 130 increases. For example, in some configurations,the humidifier configuration demonstrated in FIG. 5G may be morepreferable than the humidifier configuration demonstrated in FIG. 5F. Insome configurations, part or all of the ECP structure 133 may beconstructed from porous materials and/or may comprise microstructures orfeatures, such as ridges, ribs, depressions, and/or fenestrations, forexample but without limitation. The porous materials and/ormicrostructures or features may improve the contact area between the ECPstructure 133 and the water 130. Electrical current from an electricalconnection 132 or some other source of electricity may be fed into thereservoir 114 at one or more points along, in, or on the reservoircomprising the ECP structure 133. In some configurations, differentlevels of electrical energy may be applied to different sections orportions of the ECP structure 133. In use, the humidification chamber126 may serve to electrically and/or thermally isolate the reservoir114. In some configurations, the humidification chamber 126 need not bepresent. In some such configurations, the reservoir 114 (and electricalconnection 132, if present) may comprise the entirety of the respiratoryhumidifier 112 (e.g. the chamber 126 may not be present).

In some configurations, if an electrical current is passed from point topoint across a heater comprising electrically conductive material andhaving a substantially uniform shape and configuration, the current willfollow a path of least resistance and may travel along a line from thepoint of one electrical connection to the other. In this situation, theheating might not be as efficient as desired. Therefore, in someconfigurations, it may be desirable for the humidifier to be configuredso that electric current is spread substantially evenly across theheater to improve the efficiency of the heater. For example, asillustrated in FIGS. 6 to 13, the humidifier may comprise a heatercomprising an electrically conductive material, such as an ECPstructure. In some configurations, as demonstrated in FIGS. 7 and 8, theheater 150 may directly or indirectly interface with an electricalstructure 152. In some configurations, as demonstrated in FIG. 6 theelectrical structure may comprise a pair of electrically conductingmembers 151A, 151B extending across opposing sides of the heater 150.For example, the electrically conducting members may be located onopposing surfaces at opposing sides of the heater 150 or theelectrically conducting members may be located on the same surface butat opposing sides of the heater 150. In some configurations, theelectrically conducting members may be metallic members, such asaluminium bars. In some configurations, multiple electrically conductingmembers are positioned across opposing sides of the heater 150. Forexample, two or more electrically conducting members may be arranged inline to lie along a first side of the heater 150 and two or moreelectrically conducting members may be arranged in a line to lie along asecond side of the heater 150, the second side being located oppositethe first side. The electrically conducting members may be directly orindirectly electrically connected to a power supply so that, in use,electric current may pass along one electrically conducting member andthrough the heater 150 to the other electrically conducting member. Theelectrically conducting members may be electrically connected with theheater 150 and a power supply using any suitable configuration. Forexample, the electrically conducting members may simply contact theheater or may be adhered, welded, overmoulded or mechanically fastenedto the heater 150. In some configurations, the heater 150 is supportedby a pair of clamps 152 located on opposite sides of the heater, asshown in FIG. 7. Each clamp may comprise an electrically conductingmember, which may be a metal bar, or substantially the entire clamp mayform an electrically conducting member. Each electrically conductingmember may be positioned to lie along one side of the heater. In use,electric current E may be caused to move through the heater 150 from oneelectrically conducting member to the other, as shown in FIGS. 6 and 7.By positioning the electrically conducting members to lie along thelength or width of the heater, the current may be substantially evenlyspread across the heater. In some configurations, at least oneelectrically conducting member may comprise a printed circuit board(PCB). The PCB may have sensing functions and may comprise a thermistor,thermocouple, or other sensors or sensing modules that may be used tohelp control operation of the humidifier or other parts of a respiratorytherapy system.

The humidifier heater 150 may comprise an electrically conductivematerial, such as an ECP structure or a metal. In some configurations,as shown in FIGS. 8A to 14, the heater 150 comprises a first edge 153and a second edge 154. The second edge 154 may be viewed atapproximately 90 degrees from the first edge 153 along the same plane.The heater 150 also has a contoured first surface 155 that comprises apair of crests separated by a trough-like depression extending in onedirection along the heater 150. In this configuration, as demonstratedin FIGS. 8A, 8B, and 9A to 9D, the first surface 155 of the heater 150has a substantially convex profile when viewed from the first edge 153and has a substantially concave profile when viewed from the second edge154. The second edge 154 has a minimum thickness at one point or sectionto form a trough that extends across the heater 150 from the second edge154 to the opposing edge. The point or section at which the heater 150is of a minimum thickness may be located at a central region of thesecond edge 154. Alternatively, the point or section of minimumthickness may be located off centre or near one side of the second edge154 to encourage differential heating. In effect, the heater 150 mayhave a variable thickness along its length and/or width. In someconfigurations, as shown in FIGS. 8A, 8B and 9A to 9D, the heater 150 issubstantially circular. However, it is envisaged that the heater 150 maybe of any suitable shape, including angled shapes, curved shapes,regular shapes, and irregular shapes. The heater 150 may directly orindirectly interface with an electrical connection configured to provideelectrical energy to the heater 150. In some configurations, asillustrated in FIGS. 8A, 8B and 9A to 9D, the heater 150 may comprise apair of electrical connectors 160 to connect the heater 150 to anelectrical connection. One electrical connector 160 may be connected tothe heater 150 at opposing ends of the trough, as shown in FIGS. 8A and8B. In some configurations, the electrical connectors 160 may beconnected to electrical connections provided on the humidifier chamber127 or reservoir 114. For example, the base of the chamber 127 orreservoir 114 may comprise electrical connections, such as electricalwires that are connected to a power supply. Alternatively, the base ofthe chamber 127 or reservoir 114 may comprise any other form ofelectrical connection that may be directly or indirectly connected to apower supply. In some configurations, the electrical connectors 160 maycomprise one or more electrically conducting arms. The arms 160 may beintegrally formed with the heater 150 or the arms 160 may be attached tothe heater 150. The arms 160 may be configured to connect the heater 150to an electrical connection for supplying electrical energy to theheater. For example, each arm 160 may comprise an electrical contact 161configured to connect with an electrical connection on the chamber 127,reservoir 114 or other part or region of the humidifier. In someconfigurations, the electrical contact 161 is provided at a distal endof each arm 160. For example, each electrical contact may be located onan extension member that projects from the distal end of each arm 160,as illustrated in FIGS. 9A to 13. In some configurations, as shown inFIG. 11, the electrical contact 161 on each arm 160 may be configured toconnect with an electrical connection in the form of a spring 157. Eachspring 157 may be configured to connect to the heater 150 and to alsodirectly or indirectly connect to a power supply. The spring contacts157 may help to maintain the integrity of the electrical connectionswhen the humidifier is moved or is moving. In some configurations, theheater may form the base of the reservoir and/or the base of thehumidification chamber for a humidifier. For example, as illustrated inFIGS. 11 to 13, the heater 150 may form the base of the reservoir 114.The reservoir 114 comprises a continuous wall or walls configured to fitbetween the electrically conducting arms 160 of the heater 150, as shownin FIG. 11. The reservoir 114 may be held between the arms 160 of theheater, as demonstrated in FIG. 12. The reservoir 114 (with heater) maybe fitted within the humidifier chamber 127, as shown in FIG. 13. Insome configurations, the chamber 127 comprises a continuous wall orwalls having an inner surface or surfaces on which recessed channels 126are provided. The channels 126 are positioned to correspond with thearms 160 of the heater, so that the reservoir 114 and heater 150 can beslid into the chamber 127 by sliding the arms 160 of the heater alongthe channels 126. The projecting extension member of each arm 160 mayextend beyond the outer periphery of the chamber 127, as demonstrated inFIG. 13. In this configuration, the electrical contacts 161 provided oneach extension member may directly connect with an electrical connectionor the electrical contacts may connect with an electrical connection viaspring contacts 157, as described above. In some configurations, eacharm may comprise an electrical contact that connects with an electricalconnection provided within the respective channel of the chamber. Insuch configurations, it may not be necessary for each arm to comprise aprojecting extension member at or near its distal end. In use,electrical energy may pass through the heater from one electricalconnector to another. In some configurations, the electrical energy maypass through the heater along multiple pathways that are spreadsubstantially evenly across the heater, according to Pouillet's law:

$R = {\rho\frac{\ell}{A}}$Where:

-   -   ρ: electrical resistivity (Ωm⁻¹)    -   l: length of the heater (m)    -   A: cross sectional area of the heater (mm²)

In some configurations, each pathway of electric current E may form anarc between the electrical connections, as shown in FIG. 14. By passingelectric current across a significant area of the heater 150, the heater150 is able to heat a body of water in the reservoir 114 at a fasterrate than if current was passed through the heater 150 along a line.

In some configurations, and as demonstrated in FIG. 15A, the walls ofthe reservoir 114 may comprise vanes 144. When the reservoir 114contains water and is being heated, the vanes 144 may serve to directwater moving around in the reservoir 114 (e.g., due to convectioncurrents arising from the heating of the reservoir 114). The vanes 144may then serve to create additional turbulence, vortices, and/orswirling in the reservoir 114, which may improve the efficiency ofheating and/or mixing the water. In some configurations, the vanes 144may be heated. For example, the vanes 144 may be constructed at least inpart from an ECP material that may be heated through the use of a powersource and electrical connections similarly to those described elsewherein this disclosure. Heating the vanes 144 can further promote thecreation of turbulence, vortices and/or swirling in the reservoir 114 bydifferentially heating water in the reservoir 114. In someconfigurations, and as shown in FIGS. 15B and 15C, the reservoir 114 maycomprise an insert 146 that may be removably located within thereservoir 114. The insert 146 may comprise features 148. The features148 may comprise orifices and/or vanes 144, for example but withoutlimitation. The orifices may have an angular shape, a ‘teardrop’ shape,a curved shape, or some other shape, for example but without limitation.Similarly, the insert 146 may be used to direct water moving around inthe reservoir 114 (e.g. due to convection currents arising from theheating of the reservoir 114), which may create additional turbulence,vortices, and/or swirling in the reservoir 114, which may improve theefficiency of heating and/or mixing the water.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise”, “comprising”, and thelike, are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense, that is to say, in the sense of“including, but not limited to.”

Unless the context clearly requires otherwise, throughout thedescription and claims, the words ‘connect’, ‘connected’, ‘connecting’,‘connects’, and the like, when used to refer to electrical connections,should be interpreted to include any suitable form of electricalconnection where electrical energy is transferred from one electricallyconducting material to another. For example, the electrical connectionmay be a direct physical connection, such as physical contact betweentwo electrically conducting materials, or the electrical connection maybe a wireless connection, such as that provided by inductive charging orresonant inductive coupling or any other suitable system of wirelesslytransferring electrical energy between electrically conductingmaterials.

Where, in the foregoing description reference has been made to integersor components having known equivalents thereof, those integers areherein incorporated as if individually set forth.

The invention may also be said broadly to consist in the parts, elementsand features referred to or indicated in the specification of theapplication, individually or collectively, in any or all combinations oftwo or more of said parts, elements or features.

Reference to any prior art in this specification is not, and should notbe taken as, an acknowledgement or any form of suggestion that thatprior art forms part of the common general knowledge in the field ofendeavour in any country in the world.

Certain features, aspects and advantages of some configurations of thepresent disclosure have been described with reference to use by apatient or user. However, certain features, aspects and advantages ofthe use of the respiratory humidifier as described may be advantageouslypracticed by other people on behalf of the patient, including medicalprofessionals, medical device dealers, or medical device providers.Certain features, aspects and advantages of the methods and apparatus ofthe present disclosure may be equally applied to usage by other people.

Additionally, certain features, aspects and advantages of someconfigurations of the present disclosure have been described withreference to ECP structures and/or materials. However, certain features,aspects and advantages of some configurations of the present disclosuremay be advantageously practiced with other materials including metals orceramics. Certain features, aspects and advantages of the systems and/orapparatus of the present disclosure may equally be applied when usingstructures and/or materials that are not ECP structures and/ormaterials.

Additionally, certain features, aspects and advantages of someconfigurations of the present disclosure have pointed to the use of ECPstructures and/or materials with humidifiers, in some cases respiratoryhumidifiers for use with respiratory therapy systems. However, certainfeatures, aspects and advantages of some configurations of the ECPstructures and/or materials may be advantageously utilized with othercomponents of respiratory therapy systems (e.g. for a conduit heater ofa respiratory therapy system, etc), with nonmedical humidifiers or withother devices. Certain features, aspects and advantages of the presentdisclosure may equally be applied when using the ECP structures and/ormaterials with other systems or devices.

Although the present disclosure has been described in terms of certainembodiments, other embodiments apparent to those of ordinary skill inthe art also are within the scope of this disclosure. Thus, variouschanges and modifications may be made without departing from the spiritand scope of the disclosure. For instance, various components may berepositioned as desired. Moreover, not all of the features, aspects andadvantages are necessarily required to practice the present disclosure.Accordingly, the scope of the present disclosure is intended to bedefined only by the claims that follow.

What is claimed is:
 1. A humidifier comprising: a reservoir; and anelectrically conducting plastic (ECP) structure for heating liquid inthe reservoir, wherein the ECP structure is constructed at least in partfrom a first section comprising an ECP material and a second sectioncomprising one or more other materials.
 2. The humidifier of claim 1,further comprising a chamber for receiving the reservoir.
 3. Thehumidifier of claim 2, wherein the ECP structure is located in or formspart of the chamber.
 4. The humidifier of claim 1, wherein the secondsection does not comprise an ECP material.
 5. The humidifier of claim 1,wherein the ECP structure is molded such that the second section isintegrally formed with the first section.
 6. The humidifier of claim 1,wherein the ECP structure is constructed at least in part fromalternating sections of an ECP material and one or more other materials.7. The humidifier of claim 1, wherein at least one of the one or moreother materials comprise a non-thermally conductive and/ornon-electrically conductive material.
 8. The humidifier of claim 1,wherein at least one of the one or more other materials comprise a metalor a ceramic.
 9. The humidifier of claim 1, wherein the second sectioncomprises an electrical structure.
 10. The humidifier of claim 9,wherein the electrical structure comprises a metal configured to receiveelectrical energy.
 11. The humidifier of claim 9, wherein the ECPstructure is configured to receive electrical energy from the electricalstructure.
 12. The humidifier of claim 1, wherein the ECP structure islocated in or forms part of the reservoir.
 13. The humidifier of claim1, wherein the ECP structure has a variable thickness along its lengthand/or width.
 14. The humidifier of claim 1, wherein the ECP structurehas an irregular thickness along its length and/or width.
 15. Thehumidifier of claim 1, wherein the ECP material comprises intrinsicallyelectrically conductive plastics or polymers, and/or an intrinsicallyelectrically conducting additive or doping agent.
 16. The humidifier ofclaim 1, wherein the ECP material is in the form of an ECP materiallayer.
 17. The humidifier of claim 1, wherein the ECP structure isintegrally formed in the reservoir or a chamber for receiving thereservoir.
 18. The humidifier of claim 1, further comprising anelectrical component configured to convey energy to the ECP structure toheat liquid within the reservoir.
 19. The humidifier of claim 1, whereinthe ECP structure is configured to promote differential heating ofliquid in the reservoir.
 20. A respiratory therapy system, comprising:the humidifier of claim 1, a flow generator configured to provide a flowof gas through the humidifier, and a patient interface configured topneumatically link the flow of gas through the humidifier to a user'sairway.